Janet Shocked by Michael Jackson's Propofol Use

Nov. 19, 2009— -- Singer Janet Jackson and the rest of the Jackson clan were unaware that Michael Jackson was using propofol, a powerful sedative typically used in operating rooms, she told ABC News' Robin Roberts in an exclusive interview.

"That was, that was a shocker to me and it just -- that's serious," Jackson said. "That's heavy. That's heavy. None of us knew to that extent."

Toxicology results showed that Michael Jackson had lethal amounts of propofol in his system when he died, along with a cocktail of other prescription drugs. His death was ruled a homicide.

But the family was not naive about her brother's drug problem, Jackson said, adding that she reached out to him throughout the years but was unsuccessful.

"I did," she said. "Of course, that's what you do. Those are the things that you do when you love someone. You can't just let them continue on that way. And we did a few times. We weren't very successful."

Jackson said her brother understood that the family's motives for the interventions were out of love.

"How do I say this? Understanding. I guess that will be the best way to -- understood that it was out of love, because of caring. But when it's something like that, people can tend to be in denial," she said.

When asked if her brother was in denial about his addiction, she replied, "Possibly."

"I wish he could answer this question for you and not me," she said. "I felt that he was in denial."

Watch the Full Show: Janet Jackson In the Spotlight with Robin Roberts

The five-time Grammy award-winning artist said that she was "incredibly close" to older brother Michael; but the siblings went through long stretches without seeing one another, and Michael slowly succumbed to a dangerous spiral of drugs and addiction.

"You can't make 'em drink the water. ... I'm a true believer in prayer, a big believer in prayer -- but it's, it's something that you can't do for them. Something they have to do for themselves," she said.

In the Spotlight with Robin Roberts: Click here for your backstage pass!